B2 Content Flashcards
What is evolution?
Process by which populations living things change over a series of generations
Evidence for evolution
Fossil records
Biochemistry
Genetics
Behaviour
Plant and animal breeding
Embryology
Palaeontology
The study of fossils
Relative dating
Deeper sedimentary rock layers meaning they formed earlier —> older fossil
Radiometric dating
Technique to determine age of a rock or fossil by radioactive isotope decay rate.
What is biogeography?
The study of variation and geographic distribution of life on earth (past and present)
What are homologous structures?
Features with similar structure but different functions
Similar origins but different uses in different species
What are Analogous structures?
Similar in function and appearance but not in origin.
Convergent evolution
-Development of similar adaptations from unrelated species.
-Occupy equivalent niches on different continents
-Due to Similar environmental conditions
Embryonic Development
Late 1800s: scientists noted similarity between embryos of different species
Vestigial features
Rudimentary structures with no useful function
May have been functional in ancestor
Vestigial structures examples
Human appendix
Coccyx(tail bone)
Wisdom teeth
Muscles which move ears
Universal
Similarities in genetic code
What is gene
A segment of DNA that performs a specific function
What is artificial selection
Animal and plant breeding
Process of humans selecting and breeding individuals with desired traits
Scientific theory
Model that accounts for all known scientific evidence
Aristotle
384-322 BC
First to attempt to classify animals
First to propose spontaneous generation
George’s Louis Leclerc de Buffon
1750s
Leading naturalist
Species could change overtime which could lead to new organisms
Carl Linnaeus
1760s
Founder of bio nominal nomenclature
Erasmus Darwin
1790s
(Darwin’s grandpa)
All life developed from a single source
Jean- Baptiste Pierre
First theory of evolution with mechanism
Simples species are created with spontaneous generation and become more complex
Organisms have a desire to change for the better so they produce new parts
Lamarckism
Inheritance of a acquired characteristic. If you use it often it will pass to the next generation
Use it or lose it
Natural selection
Result of differential reproductive success of individuals caused by variations in their inherited characteristics
Environmental pressure, inheritance of characteristics and variation of the characteristics
Natural selection- Darwin
All species display inherited variation which makes them better adapted to Survive and reproduce better than others
Darwin’s theory of natural selection in 5 points
1.Overproduction
2.struggle for existence
3.variation
4.survival of the fittest
5.speciation
Darwin’s theory- over production
Number of offsprings produced by a species is greater than can survive and reproduce
Darwin’s theory-competion
Organisms of the same species(and others) must compete for the same limited resources;struggle for existence
Darwin’s theory- variation
No two individuals are exactly the same( except identical twins)
Darwin’s theory-survival of the fittest
The environment acts to select favourable traits(not create them). Those with an advantage survive and reproduce, increasing their numbers
Darwin’s theory-specification
Individuals do not change, population change overtime
Accumulation of new traits over a long period of time, leads to a different population and thus new species
Lamarks theory
Variations is acquired
Darwin’s theory
Variations is inherited
Mutations
Introduce new characteristics/variations into a population
Inherited variations-mutations
DNA is composed of nucleotide bases that form genes which give organism inherited traits
DNA is usually replicated the exact same but sometimes changes can occur
Mutations- neutral
Neutral mutations have no immediate effect on an individual’s fitness or reproductive system
Harmful mutations
May cause genetic disorders or cancer
Reduces individuals fitness
Mutation-beneficial
Provide an advantage to an individual
Has selective advantage which will likely be passed onto offspring
True or false
Mutations occur when they are needed in response to encompass changes
False they occur at random times
True or false
Harmful mutations are more common,so they can accumulate and the species will steadily degrade
False they are selected against
True or false
Mutations=diversity
True this can then lead to speciation over 1000s of generations
Inherited variations
Receive exact same DNA as parent
Inherited variation- sexual reproduction
Sexually reproducing species are variable in their phenotype(how they look)
Sexual reproduction
Half of mom and half from dad involves 2 pairs
Asexual reproduction
Involves only one parent and usually has same DNA as them
Adaption
Change in a characteristic of an organism that increases its chance of survival
3 types of adaptions we witness in nature
Structural
Behavioural
Physiological
Structural adaptions
Physical characteristics that helps an organism survive in its environment
Behavioural adaptions
Something an organism does usually in response to an external stimulus that helps them to survive
Hibernation
Migration
Physiological adaption
A process inside of a organisms body that helps it to survive in its environment
Speciation-forming a new species
Species are defined as a group of organisms that are theoretically able to reproduce with one another to make viable offspring
Allopathic speciation- physical barrier
Separating a single interbreeding population into 2 or more groups. Mutations are not shared with other populations
Allopathic speciation- natural selection
Works in separate populations inherited differences. Population evolve independently in response to varying environments
Groups are no longer sexually compatible due to accumulated physical/behavioural differneces
Darwin’s theory - speciation
Individuals do not change population change over time
Accumulation of new traits over a long period of times population become different, new species
Theory of gradualism
Speciation occurs slowly
Fossil record shows abrupt changes but we are missing many pieces
Theory of punctuated equilibrium
- Many species evolve very rapidly in evolutionary time
- Speciation usually occurs in small isolated populations, so Intermediate fossils are rare
- after an Initial burst of evolution, species are well adapted to their environment, so they do not change significantly over long time periods
Macro evolution
Evidence of divergent evolution:when species rapidly evolved into many species
Permian extinction:
unknown but suspect tectonic plates
